With respect to the effectiveness of the combustion processes taking place in the combustion chambers, adapting the air mass flow flowing through the fresh air system to a current rotational speed of the internal combustion engine, which in turn is determined by the frequency with which the process steps are cyclically carried out during the combustion in the combustion chamber, is of decisive importance. Modern fresh air systems are therefore often equipped with a flap mechanism, by means of which the line cross section of the fresh air path present in the fresh air system varies and thus the air mass flow rate that can flow through the fresh air path in a certain time interval can be adjusted.
However, problematic with such a flap mechanism often prove to be the vibration characteristics of the same, for the flap which is typically rigidly fastened to a pivot shaft is usually exposed to very high mechanical loads through the fresh air flowing through the fresh air path during the operation of the fresh air system. Since said pivot shaft is usually mounted only at the end side on a housing of the fresh air system, it is especially the combination of flap and pivot shaft that is susceptible to resonance-induced excitation of natural oscillations. Such oscillations can manifest themselves to the outside in the form of disturbing rattling or clattering noises, but always bring about increased wear of the components concerned in continuous operation.